Every number is Russ’s own rating out of 10. Russ has previously stated that he never scores in sponsored videos, so the food he reviews carries no applied pressure or bias.
Russ likes it more than the Voodoo because he can now tell it's blue raspberry; the Voodoo looked like a milky bath. The base Voodoo score is not given in this video, so there is no absolute number. He complained earlier that the zero sugar isn't shown on the front, and that it's the same product as the Mystery one.